Test 2: Wk7: 1 Tubular transport of glucose/phosphate/urea/organic - Mangiarua

Question 1

many transporter are —

Answer 1

not specific and transport a variety of similar subatances

Question 2

most organic solutes are transported only in

Answer 2

proximal tubule

Question 3

— charged organic solutes enter the cell via symporters with Na

Answer 3

neutral/ negative

Question 4

— enter via uniporters driven by the negative membrane potential

Answer 4

cations

Question 5

solutes move through a variety of pathways across the opposite membrane from which they entered in favor of — or couple via a —

Answer 5

chemical gradient, antiporter

Question 6

glucose is filtered where

Answer 6

freely at glomerulus

Question 7

glucose is taken up across the apical membrane by — and — and leaves across the basolateral membrane via —

Answer 7

SLGT2 and SGLT1; glucose uniporters GLUT

Question 8

all filtered glucose is

Answer 8

reabsorbed

Question 9

transport maximum for glucose Tm

Answer 9

375 mg/min

Question 10

Glucose first appears in the urine at the

Answer 10

plasma threshold for glucose

Question 11

true plasma threshold for glucose is

Answer 11

180-200 mg/ 100ml

Question 12

splay

Answer 12

Glucose appears in the urine prior to complete saturation of tubular reabsorptive capacity

Question 13

4 key characteristics of glucose transport

Answer 13

(1) threshold,
2) saturation (Tm),
(3) splay
(4) clearance approaching GFR at infinite plasma concentrations

Question 14

Glucose is reabsorbed by the same mechanism that reabsorbs

Answer 14

xylose, fructose and

galactose

Question 15

⬆⬆⬆ Plasma Glucose conc. blocks all reabsorption of —

Answer 15

xylose

Question 16

Renal glycosuria

Answer 16

glucose in urine as a result of a defective or missing transport
mechanism

TG = 0 or very low.

Question 17

Diabetes mellitus glucosuria due to

Answer 17

lack of insulin

TG = OK

Question 18

Pregnancy - glucosuria due to

Answer 18

⬆⬆⬆ GFR, glomerular hyperfiltration.
RBF may increase 40% in response to gestational hormones

TG = OK

Question 19

clearance of amino acids

Answer 19

0

Question 20

amino acids are — reabsorbed

Answer 20

actively reabsorbed

Question 21

filtered loads of amino acids are normally —- than their Tm

Answer 21

much less

Question 22

amino acid transport mechanisms exhibit considerable —

Answer 22

splay

Question 23

— may occur in the presence of two related amino acids

Answer 23

competitive inhibition

Question 24

the — absorbs <98% of amino acids via a — route

Answer 24

prox tubule; transcellular

Question 25

at the apical membrane amino acids enter via

Answer 25

Na or H driven transporters and exchangers

Question 26

at the basolateral membrane amino acids exit the cell via

Answer 26

amino acid exchangers

some Na dependent and some facilitated diffusion

Question 27

the — reabsorbs ~98% of filtered olgliopeptides

Answer 27

prox tubule

Question 28

small linear peptides like ANGII are

Answer 28

completely filterable

Question 29

enzymes in the brush border of the PCT break oligopeptides into — which are reabsorbed

Answer 29

amino acids

Question 30

— to — molecular wt proteins will filter

Answer 30

7000 to 70,000

Question 31

the proximal tubules reabsorb % to % of filtered protein

Answer 31

96% - 99%

Question 32

the kidney — filters urea at the — then it reabsorbs and secretes it

Answer 32

freely, glomerulus

Question 33

the tubules reabsorb — urea than they secrete which makes the amount of urea in the urine — that what is filtered

Answer 33

more, less

Question 34

primary site of urea secretion

Answer 34

thin limbs of loop of henle

Question 35

in the proximal tubule, water carriers urea by — via — or — pathways

Answer 35

diffusion via transcellular or paracellular

Question 36

some urea may be reabsorbed by — across –

Answer 36

solvent drag across tight junctions

Question 37

in the thin descending limb, urea is secreted by — through —

Answer 37

facilitated diffusion through urea transporters

Question 38

urea secretion thin ascending limb

Answer 38

same as descending (facilitated diffusion) ; transporter unknown

Question 39

Inner medullary collecting duct — urea via — involving —

Answer 39

reabsorbs urea via transcellular route involving apical and basolateral membranes

Question 40

Inner medullary collecting duct urea transporter for apical membrane

Answer 40

UT-A1

Question 41

Inner medullary collecting duct urea transporter for basolateral membrane

Answer 41

UT-A3

Question 42

— stimulates UT-A1 and UTA-3

Answer 42

ADH

Question 43

urea excretion — with increasing urine flow

Answer 43

rises

Question 44

organic anions and cations are secreted by —

Answer 44

late proximal tubule

Question 45

Organic Anions enter the cell across the basolateral membrane by one of three α-ketoglutarate antiporter mechanisms

Answer 45

OAT1, OAT2, OAT3

Question 46

Organic Anions leave the cell across the apical membrane by —

Answer 46

MRP2

Question 47

Organic Cations enter the cell across the basolateral membrane by four transport pathways: — and 3 uniporters

Answer 47

passive diffusion

OCT1, OCT2, OCT3

Question 48

Organic Cations leave the cell across the apical membrane in exchange for H+ by two antiporters

Answer 48

OCTN1, OCTN2

OC+-H+

Question 49

weak organic acids and bases are reabsorbed or secreted

Answer 49

passively

Question 50

in acidic urine a weak acid will be —

Answer 50

reabsorbed

Question 51

in alkaline urine a weak acid will be —

Answer 51

excreted

Question 52

in acidic urine, a weak base will be —

Answer 52

excreted

Question 53

in alkaline urine a weak base is —

Answer 53

reabsorbed